Field
Exemplary embodiments of the present disclosure relate to a rotor assembly having an improved cooling path, and more particularly, to a rotor assembly in which the structure of a cooling path formed in a coil turn is improved and a problem of an imbalance in heat transfer of the coil turn can be overcome.
Description of the Related Art
Generally, a generator is an apparatus which converts mechanical energy into electric energy using electromagnetic induction, and which uses the principle in which electric power is generated when a conductor rotates in a magnetic field. Such a generator uses hydrogen gas and water as a cooling medium, and has a hermetically sealed structure to prevent penetration of dust or moisture and leakage of hydrogen gas.
For ventilation in the generator, a closed circulation system using a fan installed on a shaft of a rotor is employed, and a cooler for cooling hydrogen gas is installed in the generator. Furthermore, a stator houses the rotor therein, and includes a coil, a stator core around which a coil is wound, and a frame which supports them.
When the rotor rotates, current flowing through the coil generates heat. If heat generated from the coil of the rotor is not effectively dissipated, it causes deterioration in performance of the generator.
To overcome this problem, a rotor and a rotating electric machine having a structure for cooling the rotor were proposed in Korean Patent Unexamined Publication No. 2010-0120267.
The conventional cooling structure is a structure in which cooling of a conductor assembled in a rotor body depends on only cooling fluid which is drawn into a sub-slot. However, the conventional cooling structure is problematic in that as generators are becoming larger, it is difficult to efficiently cool a rotor coil of a generator.